WindClose() closes a window on the screen and replaces the
AES wind_close function. As WindOpen() a graphic effect is used
if the window status WS_GROW bit is set to 1.
For similar raisons explained in the WindOpen() manual, the
wind_close() should never be used except in some special case.
It is important to remove the window from the internal WinDom
opened windows list with the remove_windowlist() function.